Conventional thought with respect to power systems for vehicles has been to design a lightweight vehicle for fuel efficiency. It is generally believed that a vehicle that is of lighter weight will require less power to motivate, and therefore will require less fuel input to accomplish the same power output as a heavier vehicle. Consistent with same, traditional vehicle design has been directed toward the use and/or development of light and/or small components that ultimately reduce the weight of the vehicle in which they are placed.
In connection with, and in addition to lightweight vehicles and components, various alternative power sources have been experimented with, including, for example, electric vehicles, hybrid electric vehicles, fuel cell vehicles, natural gas vehicles, neighborhood electric vehicles, electric bikes, and others. Alternative fuel sources are becoming increasingly important as government regulations and environmental consciousness become more predominant.
To this end, power sources and systems have been developed containing a flywheel which is used in combination with a motor. The flywheel is often used to generate kinetic energy for powering the vehicle.
Current flywheel automotive systems typically employ a high velocity, moderate to small mass flywheel, capable of storing and rapidly dissipating supplies of kinetic energy. Such flywheels are often coupled with a transmission adapted to permit the release of stored kinetic energy from the flywheel to the vehicle wheels. Many of these systems include a means of recharging the flywheel as it slows. The recharge is typically provided by a conventional vehicle engine.
Unfortunately, current flywheel systems incorporate a flywheel which is too light in relation to the vehicle to which it is applied. For instance, in many such systems a 2,000 lb. vehicle is provided with a flywheel of approximately 215 lbs, or roughly 1/10 the weight of the vehicle. As a result, the power generated by the flywheel will either be rapidly used, requiring almost continuous recharging, or supply very low motive power to the vehicle, resulting in minimal speed. In addition, these flywheels are commonly driven through a range of speeds from approximately 7,500 to 15,000 rpm. At such speeds, the light weight flywheel, again, will generate very little motive power. To compensate for low power, some systems have been provided with flywheels which rotate at a very high rate of speed, including in some instances up to 300,000 rpm. However, such high speed causes tremendous wear on parts and materials and, in fact, requires extremely high strength material to construct and maintain within the power source. Likewise, conventional drives have been known to fly apart at speeds approaching only 35,000 rpm. Moreover, the high speed flywheel may require a large expense of energy to bring the rotational velocity up to speed.
As indicated above, many current systems include a flywheel “recharging” engine, typically a conventional vehicle engine. In operation, if the flywheel velocity drops below a lower limit, such as below the 7,500 rpm speed noted above, the recharging engine powers on and supplies motive power to the flywheel until the flywheel reaches a designated or upper speed limit. In other words, a primary engine runs intermittently, shutting off and turning on, to control the rotation of the flywheel, allowing the flywheel to fluctuate between 7,500 rpm and 15,000 rpm. However, such devices also typically contemplate that the vehicle can be started and driven directly from the primary engine, which is a standard/conventional vehicle engine, without the assistance of the flywheel. An internal combustion engine or gas turbine is often provided as a means of recharging the flywheel system and driving the vehicle.
In addition to supplying power, kinetic energy storage systems utilizing the flywheel to store energy are also known. In such systems, the vehicle may be powered from the flywheel. Alternatively, the flywheel may be used as a generator.
As discussed, conventional sized engines are typically used to supply power to the flywheel when the flywheel falls below a minimum speed. As indicated above, it is also common for the flywheel to be bypassed to attain a direct drive between the engine and the vehicle wheels. Common in many such systems, a spinning wheel is provided in conjunction with a conventional sized engine. These systems contemplate driving a vehicle by the engine. Further, while providing a spinning wheel, the spinning wheel is typically not geared up to a level of speed to be an effective form of energy output.
Flywheels may also be used as a power supplement to enhance the overall efficiency of an engine. In such cases, the flywheel is not used as the main driving force. For example, a flywheel, which is connected to an electric motor, may be provided as a power storage means for storing mechanical rotational energy. In addition, a selectively operable clutch may be used to connect the flywheel to the driveshaft for delivering stored power to an engine. The flywheel is selectively engaged with the engine at predetermined times to provide stored mechanical energy to the engine.
In addition, it is known to provide a flywheel as an energy enhancer, such as a hybrid power system. For instance, a vehicle may be provided with a prime mover or engine, an energy storage device or flywheel, a clutch between the engine and flywheel, and a continuously variable transmission unit. Similar to other devices, the prime mover is decoupled from the flywheel and shut off to terminate fuel consumption when the flywheel reaches a predetermined level of speed. The internal combustion engine is generally the prime mover for the vehicle, while the flywheel is placed in driving connection with the transmission and the engine when the vehicle is to be driven under a heavy load. In other words, the hybrid power system is provided for assisting the prime mover and powering the vehicle. Similarly, electrically powered motor vehicles having a flywheel and a motor generator are also known. In these systems, the flywheel is used as an energy buffer to provide surge power for accelerating the vehicle and for hill climbing, as a compliment to the relatively low, steady power provided by the fuel burning power source. An electric motor can also be provided to convert the power generated from the flywheel or the power source to mechanical motive power.
In addition to single flywheel systems, other variations on flywheel systems have been experimented with. For instance, devices containing multiple, small, lightweight flywheels have been attempted. These systems often rotate the flywheels in opposite directions to cancel out the gyroscopic force generated by the rotating wheels. Likewise, a number of flywheels may be rotated while others are isolated and/or run idle in a single system. The theory in many such systems is that the use of a number of small flywheels enables the power unit to be made smaller and lighter than if a single wheel were used. Vehicle propulsion and regenerative braking arrangements, including an energy storage flywheel coupled to an automatic transmission have also been attempted. Similarly, various flywheel forms are known, such as flywheels having a mass concentrated towards the outside of the shape of same, as well as flywheels of conical, radial, spheroid, toroid, and elliptical shape, constructed from metal, epoxies, ceramics, wood or plastic.
In general, disadvantages inherent in many such designs are, among other things, without a transmission between the primary engine and the flywheel, the systems are not durable enough to last very long. Namely, if a flywheel is provided of sufficient weight to generate enough power to motivate a vehicle, it would need a transmission between the primary motor and the flywheel or it would place too much strain on either the engine or the clutch. However, if the flywheel provided is lightweight, so as to avoid the need for a transmission, it would be ineffective in generating sufficient motive power. Further, often times the flywheel is positioned to rotate about a vertical axis. In such cases, the flywheel is prone to wobble, and causes significant wear on the lower component holding or supporting same in place. Moreover, many such systems incorporate a flywheel that is not heavy enough to generate effective, efficient motive power. In fact, current flywheel systems are coupled to a conventional sized engine. The conventional engine adds significant weight and is contemplated to provide the primary motive power to the vehicle. As a result, the flywheel is provided as a power supplement of minimal weight. Moreover, the flywheel is generally not appropriately geared to the vehicle wheels at a ratio effective to convey sufficient motive power from the flywheel alone. To date, an effective, efficient system has not been available in which a large mass rotating wheel generates the primary motive power for a vehicle, machine, or device.
Accordingly, what is needed in the art is an improved motive power source for a vehicle in which a large mass wheel may be used in combination with a small motor to generate efficient and strong power for a vehicle, machine, and/or device, resulting in reduced emissions and improved fuel economy. A further need exists for such features in a vehicle. Moreover, a need exists for providing a large mass wheel approximately geared between the engine and vehicle wheels for providing optimum output from the large mass wheel, which provides the primary source of motive power to the vehicle.